The present invention generally relates to electronic switching matrices. In particular, the present invention relates to compact, millimeter wave switching matrices for use in electronic beam forming applications.
Electronic switching matrices (ESMs) are used in electronic communications networks to route signal energy from appropriate inputs to appropriate outputs. ESMs are frequently employed in communications network elements such as earth stations and satellites. In a satellite, for example, an ESM may be used to switch signal energy received over an uplink channel to the appropriate downlink channel.
ESMs typically have two stages. In the first stage, the incoming signal energy is split by use of power splitters (for example, by a Wilkinson power splitter.) Once each of the incoming signals is split, the split signals are fed into a series of switches. The switches are often implemented using Wilkinson power combiners.
One of the difficulties encountered with conventional implementations of ESMs is the large power loss associated with the use of Wilkinson power combiners. At each stage of combination, there is approximately a 3 dB (half-power) loss. Since the signal typically goes through multiple levels of combination, this loss is very significant. The need to amplify the signal along the way may be costly in terms of both physical dimension and weight of the ESMs. This poses particular problems in ESMs for satellite applications, where size, weight and power conservation are extremely important factors in design cost, performance, and reliability.
Another difficulty with conventional ESMs is that the splitting stages and the switching stages are typically interconnected by coaxial cable or similar means. In high frequency applications, impedance mismatch in the connectors may cause substantial signal energy loss. Also, this cabling further adds to the physical dimension and weight of the ESM. Again this may increase costs substantially.
Yet another difficulty with prior ESMs is their failure to provide for scalability, particularly as the signal frequency handled by the communication systems increases. The failure to provide this scalability causes substantial redesign costs as new technologies increase the frequencies at which communications systems operate.
The presence of these and other problems in past ESMs demonstrates that a need has long existed for an improved ESM.
It is an object of the present invention to provide an electronic switching matrix.
Another object of the present invention is to provide an electronic switching matrix that reduces mismatch in the connections between the components of the switching system.
Still another object of the present invention is to provide an electronic switching matrix that provides a small, low-loss, microwave switching matrix for applications where a large number of input ports need to be connected to a large number of output ports.
Yet another object of the present invention is to provide an electronic switching matrix that provides for wideband performance, allowing low frequency signal and millimeter wave signal switching from the input ports to the output ports.
One or more of the foregoing objects are met in whole or in part by a preferred embodiment of the present invention that provides a compact ESM that utilizes low-loss, high frequency switches in the switching modules. The ESM includes several splitting modules arranged along a first axis. Each splitting module includes a signal input and several splitter outputs. The ESM further includes several switching modules arranged along a second axis perpendicular to the first axis. Each switching module generally includes switching inputs coupled individually to an output of each of the splitting modules.
The ESM is further characterized by the couplings between the splitter modules and the switching modules. The couplings are formed by mating male and female connectors integrated into the splitting modules and the switching modules. The couplings support extremely high frequency operation. The splitting modules and the switching modules may thus be coupled closely together to form a dense, high frequency, switching matrix. To this end, the splitting and the switching modules may be stacked upon one another, and may be hermetically sealed.
In one embodiment, the ESM is configured as a 128 input by 52 output switching matrix. In this configuration, for example, 128 splitter modules may be used in conjunction with 13 switching modules. In another embodiment, the ESM is configured as a 512 input by 52 output switching matrix. In this configuration, 512 splitter modules may be used in conjunction with 13 switching modules.
The splitter modules may be arranged along a first side and an opposite side of the switching modules. The splitter modules may thus be evenly distributed between the first and opposite sides of the switching modules to increase the density of the ESM. Furthermore, the splitter modules may be arranged along each of the four sides of the switching modules, thereby providing an extremely high density ESM.